1. Field of the Invention
This invention pertains to method and apparatuses for resawing shake blanks into a pair of tapered shakes each with a sawn surface and an opposite naturally-split surface.
2. Description of the Prior Art
A typical shake is anywhere from 4 to 14 inches or more in width and from about 18 to 24 inches long with thickness ranges from one-half to 3/4 inch and 3/4 to 11/4 inch at the butt tapering to 1/8 inch or thinner at the tip. Other thicknesses and lengths are also possible. The most commonly accepted practice for producing these shakes is to split a blank or board of the desired thickness from a shake block then pass the board through a thin bandsaw to form two shakes, each with a split face and a sawn back. Generally, the sawing is accomplished by sawyers who manually guide the board diagonally through the saw to produce the thin tips and thick butts.
Many attempts have been made to mechanize the resaw process to eliminate the hazards of manual resawing, to increase production, provide more uniformity in the taper of the shakes, and increase yield. Generally, these machines have not been successful since the irregularities of a split piece of wood has defied uniformly good final shakes. One such machine is shown in U.S. Pat. No. 3,554,250 which passes a board endwise between two rollers while shifting the rollers laterally of a cutting plane to produce a cut which attempts to approximate a diagonal cut through the board. This type of machine, however, is not able to hold the board stable while cutting, cannot adequately compensate for curved or twisted boards and does not adequately compensate for boards which may not be of a uniform thickness throughout.